If you’re the DIY type and want to turn a regular glass tank into a reef ready setup, you could drill all of the required holes freehand, but you run the risk of putting them in the wrong place. Instead of trying to do it all by hand and eyeballing it, create a template instead. The template will allow you to put the holes in the perfect spot each time, and it will prevent the drill bit from jumping about during the drilling process. If you make the template out of wood, it can be used over and over again. Regardless of the template’s material, be sure to secure it to the tank with clamps and always measure a couple of times before cutting.